The present disclosure relates to a power supply device, a power supply managing device, a method for detecting the connection position of a power supply device, and a power supply system.
Series and parallel connection of power sources or loads are the basis of the electrical circuit. In the case of the passive load, series and parallel connection does not involve principle difficulty and the corresponding electrical wiring can be realized. In contrast, in the case of the power source, danger exists unless the voltage or current capacity thereof is taken into consideration, and mere series and parallel connection cannot be made.
For example, in the case of parallel connection of cells, a condition that the output voltages of the individual cells connected in parallel are equal to each other and a condition that the kinds of cells (in addition, even manufacturer and lot) are the same are necessary. This is because of the following reason. Specifically, if the kinds of individual cells are different, the charge and discharge characteristics are different. Thus, even when the voltage is the same at the initial stage, imbalance of the voltage occurs over time. This causes adverse effects that any cell charges another cell and that stress is applied only to a given cell.
In the series connection, the current capacity of the whole cells connected in series depends on the lowest current capacity among the cells, and effective connection is impossible unless the current capacities of the respective elements are equivalent to each other. However, by sufficiently equalizing the electrical characteristics or taking a countermeasure such as control of current distribution to the respective elements (in the case of parallel connection) or equalization of the current capacity (in the case of series connection), series and parallel connection of power sources and switching of the connection are also permitted and are used in practice.